The restaurant

Picture a busy restaurant where orders live on scraps of paper. One gets lost. Two cooks make the same dish. Nobody knows if table 7 has been served.

Real organisations have the same problem with loan applications, insurance claims, patient referrals and service requests. Pega is software that keeps that work on rails: every piece of work has a place in a process, a person who owns the next move, and rules about what is allowed.

In Pega, one piece of work is called a caseOne piece of work followed from start to finish, like a single order ticket.. It moves through stagesA phase of the work, such as Ordered, Cooking, Plating, Served., and each stage has stepsOne small job that a person (or the system) must complete before the case can move on..

At every step, a person looks at a screen: the order pad. It has fields to fill in and buttons to press. Pega's modern screen system is called ConstellationPega's current way of drawing screens, using a modern web design system., and it comes with a standard set of controls.

Sometimes the standard set is not enough. Maybe you need a button that calls a phone system, or a field that shows a star rating. Then you build your own piece and plug it in. That piece is a custom DX componentA small, custom screen part you write yourself and publish into Pega, so it can be used like a built-in one., and building one is what the rest of this story is about.

But first, how does Pega draw a screen at all? That is the next chapter, and it is the idea that makes everything else click.